A method to recover water-wave profiles from pressure measurements

An operational formulation is proposed for reconstructing a time series of water surface displacement from waves using measurements of pressure. The approach is based on the fully nonlinear formulation for pressure below traveling-wave solutions of Euler’s equations developed by Oliveras, Vasan, Deconinck and Henderson. Its validity is tested using experiments in which both the pressure and the surface displacement are measured. The experiments include a wave system that is Galilean invariant – cnoidal waves, and wave systems that are not – reflected cnoidal waves and wave groups. We find that since the proposed formulation is nonlinear, it reproduces the amplitude spectrum of the measured surface displacements better than the hydrostatic model and better than the linear model that takes into account the pressure response factor due to small amplitude waves (the transfer function). Both the proposed formula and the transfer function reconstruct the surface reasonably well, with the proposed formula’s being about 5% more accurate.     

Nanocrystalline Ni0.6Zn0.4Fe2O4: A novel semiconducting material for ethanol detection

The structure and crystal phase of the nanocrystalline powders of Ni_1−xZn_xFe₂O₄ (0 ≤ x ≤ 0.5) mixed ferrite, synthesized by ethylene glycol mediated citrate sol-gel method, were characterized by X-ray diffraction and microstructure by transmission electron microscopy. Further studies by Fourier transform infrared spectroscopy were also conducted. Moreover, DC electrical properties of the prepared nanoparticles were studied by DC conductivity measurements. The response of prepared Ni_1−xZn_xFe₂O₄ mixed ferrites to different reducing gases (ethanol, hydrogen sulfide, ammonia, hydrogen and liquefied petroleum gas) was investigated. In particular, Ni_0.6Zn_0.4Fe₂O₄ composition exhibited high response to 100 ppm ethanol gas at 300 °C. Incorporation of palladium further improved the response, selectivity and response time of Ni_0.6Zn_0.4Fe₂O₄ to ethanol gas with the blue shift in the operating temperature by 25 °C.     

三维荧光光谱结合自加权交替三线性分解算法检测农药类混合物

三维荧光光谱技术与自加权交替三线性分解(SWATLD)算法相结合,对三类农药混合溶液进行检测。在乙腈溶剂中配制西维因、速灭威和三唑磷不同浓度比的混合溶液为测量样品(西维因、速灭威及三唑磷的最佳激发波长/发射波长分别为285/325,305/345和265/305 nm),利用荧光光谱仪获取样品的三维荧光光谱,经过空白扣除以及激发与发射校正,有效地去除仪器误差以及散射产生的影响,得到样品的真实光谱。采用基于自加权交替三线性分解算法对测得的光谱数据进行分析,得到的三种农药的平均回收率为96.9%±1.9%,99.8%±1.0%和100.8%±3.2%。根据SWATLD算法预测结果,计算三类农药的预测均方根误差(RMSEP)值为0.616×10-2,0.539×10-2和0.374×10-2 μg·mL-1,低于平行因子(PARAFAC)分析法预测结果的RMSEP值,且最低检测限均在0.005~0.022 μg·mL-1范围内。和PARAFAC算法相比较,突出了SWATLD算法的优势,表明该算法对光谱重叠严重的三类农药混合物有较好的分解能力。     

Gas-assisted magnetic separation for the purification of proteins in batch systems

In this paper, gas-assisted magnetic separation (GAMS), a technique that combines magnetic separation with flotation, was investigated for the potential large-scale separation of proteins. The GAMS process includes adsorption of target proteins and magnetic separation to recover protein-loaded magnetic particles from the dilute biosuspension with the assistance of bubbles. Microsized ethylenediamine-functionalized poly(glycidyl methacrylate) superparamagnetic microspheres (MPMs) and bovine serum albumin (BSA) were used as a model system. The feasibility of GAMS for capturing BSA-loaded MPMs from an appropriate medium was shown. High recovery of BSA-loaded MPMs was obtained by simple adjustment of the initial solution pH without extra detergents and antifoaming agents. The GAMS conditions were consistent with the adsorption conditions, and no proteins were desorbed from the MPMs during this process. Under the optimal conditions, the separation rate and recovery percentage reached 410 mL/min and 98% in 0.61 min, respectively. Conformational changes of BSA during the GAMS process were investigated by fluorescence spectroscopy and circular dichroism spectrometry.     

大型差异数据库中入侵路径恢复模型分析

在大型差异数据库中,假设入侵特征存在较大的伪装,将难以形成入侵判断的依据,无法建立入侵路径恢复模型。提出基于敏感性数据挖掘方法的大型差异数据库中入侵路径恢复方法模型。利用主成分分析方法搜索大型差异数据路中的入侵路径,为模型的建立提供准确的数据基础,利用敏感性数据挖掘方法能够检测到入侵路径的特征,从而能够建立准确的入侵路径模型。实验结果表明,利用改进方法进行大型差异数据库中入侵路径恢复,能够提高恢复的准确性,从而保证大型差异数据库的安全。     

Effects of a vocally fatiguing task and systemic hydration on phonation threshold pressure

Phonation threshold pressure (PTP), effort for speaking, and vibratory closure pattern were assessed in 4 women with normal untrained voices after 2 hours of loud reading. PTP generally increased after this vocally fatiguing task at conversational pitch and 10%, 50%, and especially 80% of the pitch range. Increased systemic hydration by drinking water appeared to attenuate and/or delay the elevation of PTP for 3 subjects, at least at the highest pitch tested. Effort for speaking increased consistently throughout the loud reading task and subsequently decreased after 15 minutes of vocal silence. Upon videostroboscopic examination of the larynx, 3 subjects demonstrated spindle-shaped vibratory closure patterns on occasion after loud reading. The results provide preliminary support for increasing water consumption to reduce or delay some vocal-function changes after prolonged loud phonation in untrained speakers.     

许—模型下误差方差的可容许估计

本文讨论了在许－模型下非负二次估计类中误差方差的可容许估计的条件。     

五大连池矿泉微量元素含量对疗养康复的医疗价值研究

五大连池矿泉属铁硅质、重碳酸盐镁钙型复合型医用矿泉水，含有丰富的宏、微量元素，具有很高的医疗保健价值，可治疗各型慢性胃炎、胃十二指肠溃疡、结肠炎、银屑病、风湿性关节炎、缺铁性贫血、高血压病、植物神经功能紊乱等多种疾病，广泛应用于临床，收到良好效果。     

基于点线插值的离散最小二乘后处理方法

构造了一种基于点线插值有限元的后处理方法,这种后处理方法具有好的超收敛性和最小二乘的稳定性.